This invention relates to an electronic pan and tilt apparatus that can change a direction of an electronic still or video camera, and also relates to a camera that employs the same.
Conventionally, in a camera with remote operation capability such as a video camera operated by remote control, a motor drives the camera through a gear mechanism to change a direction thereof by moving a camera unit up and down or left and right.
Many of such cameras are equipped with a zoom function from 8 to 20 magnifications. It is also common to pan and tilt the camera in multiple directions within an operating range of the camera. In setting a shooting direction, a direction toward a subject and a zoom magnification are determined while viewing an image on a monitor. Alternatively, a predetermined direction and a zoom magnification are stored in a memory for automatic adjustment of the camera.
Such a pan/tilt camera is suitable for shooting a subject at a far and wide area to display a large figure on a monitor. However, as a door camera to just swing vertically to see a person according to a height, or as a camera for shooting inside a house, it is insufficient to recognize the subject if a camera has a short focal point and a lens view angle of approximately 50° directed in only two or three directions.
In recent years, such a single focus lens cameras has become smaller, and the whole system including a lens, an imaging unit and a processing unit can fit into even a two square centimeter area. However, when such a camera is driven by a motor with gears to tilt like the conventional device, a size of the combined device increases due to the tilt apparatus, making it difficult to take advantage of the small camera size.
Even in the case that only two or three shooting directions are necessary, the conventional control method needs to detect the shooting directions and store the direction information in a memory. Thus, it is difficult to reduce a cost and a size of the device and to simplify the control mechanism.
Also, when shooting a far and wide area, a subject is mostly in a horizontal position. For example, only a limited vertical shooting range is necessary for an outdoor monitoring camera, as there is no need to shoot a sky or a ground. It is sufficient to move a camera slightly up and down to cover a difference in heights among persons when shooting a participant in a group during a TV conference. For such a use, the conventional camera, which has the same range in both vertical and horizontal directions, has more than enough pan/tilt capability, resulting in an unnecessary high price.
In view of resolving the problems, an object of the present invention is to provide a camera with a simple and low cost pan/tilt apparatus.
Further objects and advantages of the invention will be apparent form the following description of the invention.